JP2013107936A - Methacrylic resin and melt molded article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a methacrylic resin having excellent flow moldability and chemical cracking-resistance as well as excellent transparency and surface hardness that can make thermoplastic molding, and to provide a melt molded article thereof.SOLUTION: There are provided: the methacrylic resin containing 60-90 mass% of methacrylic ester monomer unit, and 10-40 mass% of at least one kind of fluorine group-containing vinyl monomer unit that is copolymerizable with the methacrylic ester monomer unit; and the melt molded article formed by the methacrylic resin.

Description

  The present invention relates to a methacrylic resin and a melt-molded product thereof.

So-called sanitary products such as bathtubs and washstands have been widely used in the past, but those made of earthenware or stainless steel have been widely used in recent years. However, in recent years, they are lightweight, resistant to breakage, aesthetics, ease of installation, etc. From this point of view, many products made of resin have been used.
In addition, as a material for sanitary products such as resin bathtubs and bathtubs, washstands, vanities, and kitchen counters, thermoplastic molding materials are required to simplify the production process and reduce production costs.

  Furthermore, such a sanitary product made of resin can be formed using acrylic resin on the surface and base material from the viewpoint of emphasizing surface scratch resistance, surface gloss, weather resistance, hydrolysis resistance, etc. It is being considered.

However, thermoplastic acrylic resins generally lack solvent resistance, and cracks and crazes may occur when a molded product of methacrylic resin comes into contact with organic solvents or commercially available chemicals. There are still insufficient studies for practical application to sanitary products.
Further, depending on the sanitary use, transparency may be required in order to replace glass products, improve designability, and clearness. Improvement is also required from this viewpoint.

As a conventional technology of a sanitary thermoplastic resin composition, Patent Document 1 discloses an acrylic resin, a granular additive (granular polytetrafluoroethylene resin powder) having an elastic modulus of 15% or less of an acrylic resin, and a surface-treated inorganic material. An acrylic resin composition containing a filler has been introduced.
Patent Document 2 introduces a sanitary product using an acrylic plate as a surface layer and reinforced with other resin such as ABS (acrylonitrile-butadiene-styrene).
Further, Patent Document 3 proposes a technique for improving the scratch resistance, impact resistance, and chemical crack resistance of a molded article by adjusting the molecular weight of acrylic and adding silica.

JP 2009-235207 A JP 2005-7870 A Japanese Patent Laid-Open No. 9-207196

However, although the acrylic resin composition disclosed in Patent Document 1 has improved chemical crack resistance as compared with the acrylic resin alone, the surface is caused by the decrease in transparency due to the additive and the inclusion of a component having a low elastic modulus. There is concern about a decrease in hardness.
In addition, the sanitary product disclosed in Patent Document 2 is not only inferior in productivity because it needs to be laminated, but the surface acrylic plate contains a soft component, so that the surface hardness is practically used. Not enough.
Furthermore, the composition disclosed in Patent Document 3 is a composition for pouring a monomer into a fixed mold for cast polymerization, and is not suitable for melt molding such as injection molding or extrusion molding, and is easy to process. There is a problem of being scarce.

  Therefore, an object of the present invention is to provide a resin that can be melt-molded, is excellent in fluid moldability and chemical crack resistance, and is also excellent in transparency and surface hardness.

As a result of intensive studies in order to solve these problems of the prior art, the present inventors have copolymerized a vinyl monomer containing at least one fluorinated group into a methacrylic acid ester monomer. The present inventors have found that the above problems can be solved by using the methacrylic resin obtained by the above, and have completed the present invention.
That is, the present invention is as follows.

[1]
Methacrylic acid ester monomer unit: 60 to 90% by mass,
At least one fluorine-containing vinyl monomer unit copolymerizable with the methacrylic acid ester monomer unit: 10 to 40% by mass;
A methacrylic resin.
[2]
When the total of at least one fluorine group-containing vinyl monomer unit copolymerizable with the methacrylic acid ester monomer unit and the methacrylic acid ester monomer unit is 100 parts by mass,
Other than the at least one fluorine group-containing vinyl monomer unit copolymerizable with the methacrylic acid ester monomer unit, other vinyl monomer units copolymerizable with the methacrylic acid ester monomer unit may be acrylic. The methacrylic resin according to [1] above, containing 0 to 20 parts by mass of an acid ester monomer unit.
[3]
The methacrylic resin according to [1] or [2], wherein the weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) is 50,000 to 250,000.
[4]
A melt-molded article using the methacrylic resin according to any one of [1] to [3].
[5]
The melt molded article according to [4], which is a sanitary molded article.

  According to the present invention, it is possible to provide a methacrylic resin that can be molded by thermoplasticity, is excellent in fluid moldability and chemical crack resistance, and is also excellent in transparency and surface hardness.

It is a schematic explanatory drawing of the chemical crack-proof test by a bending foam method.

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described. The present invention is not limited to the following description, and various modifications can be made within the scope of the gist thereof.
In the present specification, the monomer component before polymerization is referred to as “˜monomer”, and “monomer” may be omitted.
In addition, the structural unit constituting the polymer is referred to as “˜monomer unit”, and may be simply referred to as “˜unit”.

[Methacrylic resin]
(Constitution)
The methacrylic resin of this embodiment is
Methacrylic acid ester monomer unit: 60 to 90% by mass,
At least one fluorine-containing vinyl monomer unit copolymerizable with the methacrylic acid ester monomer unit: 10 to 40% by mass;
Containing.

<Methacrylate monomer unit>
The methacrylic acid ester monomer unit constituting the methacrylic resin of the present embodiment is not particularly limited as long as the effects of the present invention can be achieved, but a preferable example is represented by the following general formula (1). Monomer.

In the general formula (1), R ₁ represents a methyl group.
R ₂ represents a group having 1 to 12 carbon atoms, and may have a hydroxyl group on the carbon.

  Examples of the methacrylic acid ester monomer unit include butyl methacrylate, ethyl methacrylate, methyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, methacrylic acid (2-ethylhexyl), methacrylic acid. Examples include acid (t-butylcyclohexyl), benzyl methacrylate, methacrylic acid (2,2,2-trifluoroethyl), and a typical one is methyl methacrylate. These may be used alone or in combination of two or more.

<At least one fluorine group-containing vinyl monomer unit copolymerizable with a methacrylic acid ester monomer unit>
At least one fluorine group-containing vinyl monomer unit (hereinafter simply referred to as a fluorine group-containing vinyl monomer) that can be copolymerized with a methacrylic acid ester monomer unit constituting the methacrylic resin of this embodiment. Is not particularly limited as long as the effects of the present invention can be achieved, but preferred examples include vinyl fluoride, 1-fluoroethen-1-ol, and 1-fluoroethene-1-thiol. (Z) -2-fluoroethen-1-ol (Z) -1-mercapto-2-fluoroethen-1-ol, (E) -1-mercapto-2-fluoroethen-1-ol, (E) -2-fluorovinyl alcohol, vinylidene fluoride, 1,2-difluoroethene, (E) -1,2-difluoroethene, (Z) -1,2-difluoroethene, (E) -1 2-difluoroethen-1-ol, (Z) -1,2-difluoroethen-1-ol, 2,2-difluoroethen-1-ol, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, trifluoro Methyl trifluorovinyl sulfide, (trifluoromethyl) (trifluorovinyl) ether, (heptafluoropropyl) (trifluorovinyl) ether, 1,1,1,2,3,3,3-heptafluoropropane-2- Yltrifluoroethenyl ether, 5- (trifluoromethyl) tridecafluoro-3,6-dioxa-1-nonene, methyl 5-oxanonafluoro-6-heptenoate, β, β-difluorostyrene, α, α- Difluoroacetophenone, (Z) -α, β-difluorostyrene, α, 4 -Difluorostyrene, 2,4-difluorostyrene, 2,5-difluorostyrene, 2,6-difluorostyrene, (E) -α, β-difluorostyrene, 1-phenoxy-2,2-difluoroethene, 4, β -Difluorostyrene, 2,3-difluorostyrene, α, β, β-trifluorostyrene, pentafluorostyrene, 1-methylethenyl trifluoroacetate, allyl trifluoroacetate, ethyl trifluoropropenoate, acrylic acid 2,2,2 -Trifluoroethyl, trifluoromethyl methacrylate, methyl 2- (trifluoromethyl) acrylate, methyl 4,4,4-trifluorocrotonate, 1- (trifluoromethyl) -2,2,2-acrylic acid Trifluoroethyl, 2- (trifluoromethyl) acrylic acid 2,2,2-tri Fluoroethyl, methyl 3- (trifluoromethyl) -4,4,4-trifluoro-2-butenoate, 2,2,3,3,3-pentafluoropropyl 2-fluoroacrylate, 1,1,1, 6,6,6-hexafluoro-4-hydroxy-3-hexen-2-one, methacrylic acid (1,1,2-trifluoroethyl), methacrylic acid (1,2,2-trifluoroethyl), methacryl Acids 2,2,2-trifluoroethyl, ethyl 4,4,4-trifluoro-2-butenoate, 2-butenyl trifluoroacetate, (E) -1-methyl-1-propenyl trifluoroacetate, 3- 2,2,2-trifluoroethyl butenoate, methyl α-fluoroacrylate, fluoromethyl acrylate, vinyl trifluoroacetate, trifluoromethyl acrylate, 1,1,1 -Trifluoro-4-hydroxy-3-buten-2-one, 4,4,4-trifluorocrotonic acid and the like.

  Particularly preferred examples of the fluorine group-containing vinyl monomer unit include monomer units represented by the following general formula (2).

R ₃ and R ₄ in the general formula (2) each have a fluorine atom in at least one of them, and are functional groups composed of carbon and hydrogen atoms.
Examples of the monomer represented by the general formula (2) include trifluoromethyl acrylate, 2-fluoroacrylic acid, 2,2,2-trifluoroethyl, and 1- (trifluoromethyl) -2,2 acrylate. , 2-trifluoroethyl, 2- (trifluoromethyl) acrylic acid 2,2,2-trifluoroethyl, 2-fluoroacrylic acid 2,2,3,3,3-pentafluoropropyl, α-fluoroacrylic acid Methyl, fluoromethyl acrylate, 2,2,2-trifluoroethyl acrylate, trifluoromethyl methacrylate, methyl 2- (trifluoromethyl) acrylate, pentafluoroethyl methacrylate, 2,2,3 acrylic acid 3,3-pentafluoropropyl, 2-fluoroacrylic acid 2,2,3,3-tetrafluoropropyl, α-fluoro Ethyl acrylate, methyl 2- (fluoromethyl) propenoate, methacrylic acid (1,1,2-trifluoroethyl), methacrylic acid (1,2,2-trifluoroethyl), 2-fluoroacrylic acid 2,2 , 2-trifluoroethyl, 2,2,2-trifluoroethyl methacrylate, methacrylic acid (heptafluoropropyl), 2,2,3,3,4,4,4-heptafluorobutyl acrylate, hepta methacrylate Fluoroisopropyl, 1,1,2,2-tetrafluoroethyl methacrylate, 1,2,2,2-tetrafluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl acrylate, methacrylic acid (1, 1,2,2,3,3-hexafluoropropyl), 1,1,2,3,3,3-hexafluoropropyl methacrylate, Tacrylic acid (1,2,2,3,3,3-hexafluoropropyl), 1- (trifluoromethyl) -2,2,2-trifluoroethyl methacrylate, 2,2,3,4, acrylic acid 4,4-hexafluorobutyl, acrylic acid 2,3,3,4,4,4-hexafluorobutyl, methacrylic acid (1,1,2,2,3,3-hexafluoropropyl), methacrylic acid (1 , 2,2,3,3,3-hexafluoropropyl), 1- (difluoromethyl) -1,2,2,2-tetrafluoroethyl methacrylate, 2,2,3,4,4,4 acrylic acid -Hexafluorobutyl, 2,3,3,4,4,4-hexafluorobutyl acrylate. Among these, typical ones having good polymerization stability are 2,2,2-trimethyl methacrylate in which R ₃ is a methyl group and R ₄ is CH ₂ CF ₃ in the general formula (2). Fluoroethyl. These may be used alone or in combination of two or more.

Content of the fluorine group containing vinyl monomer unit which comprises the methacrylic resin of this embodiment is 10-40 mass% in the methacrylic resin of this embodiment.
From the viewpoint of fluidity and chemical crack resistance, it is necessary to be 10% by mass or more, and from the viewpoint of surface hardness and heat resistance, it is necessary to be 40% by mass or less.
Preferably it is 15-40 mass%, More preferably, it is 20-40 mass%, More preferably, it is 20-35 mass%.

The methacrylic resin of this embodiment is
When the total of at least one fluorine group-containing vinyl monomer unit copolymerizable with the methacrylic acid ester monomer unit and the methacrylic acid ester monomer unit is 100 parts by mass,
Other than the at least one fluorine group-containing vinyl monomer unit copolymerizable with the methacrylic acid ester monomer unit, other vinyl monomer units copolymerizable with the methacrylic acid ester monomer unit (hereinafter, As other vinyl monomer units other than the fluorine group-containing vinyl monomer, it may contain 0 to 20 parts by mass of an acrylate monomer unit.

<Other vinyl monomer units copolymerizable with methacrylic acid ester monomer units other than at least one fluorine group-containing vinyl monomer unit copolymerizable with methacrylic acid ester monomer units>
Furthermore, it can be copolymerized with a methacrylic acid ester monomer unit other than a fluorine group-containing vinyl monomer unit, which can be copolymerized with the methacrylic acid ester monomer unit described above, constituting the methacrylic resin of this embodiment. Other vinyl monomer units (hereinafter, simply referred to as other vinyl monomer units other than fluorine group-containing vinyl monomer units) may be acrylics represented by the following general formula (3). Examples include acid ester monomers.

In the general formula (3), R ₅ is a hydrogen atom, and R ₆ is an alkyl group having 1 to 18 carbon atoms.
For example, α, β-unsaturated acids such as acrylic acid and methacrylic acid, divalent carboxylic acids containing unsaturated groups such as maleic acid, fumaric acid, itaconic acid, cinnamic acid, and alkyl esters thereof; styrene, o-methylstyrene M-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, -Styrene monomers such as ethyl styrene, p-tert-butyl styrene, isopropenyl benzene (α-methyl styrene); 1-vinyl naphthalene, 2-vinyl naphthalene, 1,1-diphenylethylene, isopropenyl toluene, iso Propenylethylbenzene, isopropenylpropylbenzene, isopropenylbutylbenze Aromatic vinyl compounds such as isopropenylpentylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride N-substituted maleimides such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide, etc .; Amides such as acrylamide and methacrylamide; Ethylene glycol di (meth) acrylate, diethylene glycol di Acrylates the hydroxyl groups at both ends of ethylene glycol or its oligomers such as (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, etc. Esterified with acid or methacrylic acid; hydroxyl group of two alcohols such as neopentyl glycol di (meth) acrylate and di (meth) acrylate esterified with acrylic acid or methacrylic acid; trimethylolpropane, pentaerythritol And polyhydric monomers such as divinylbenzene, which are esterified with a polyhydric alcohol derivative such as acrylic acid or methacrylic acid.

  In the methacrylic resin of this embodiment, other vinyl monomer units other than the fluorine group-containing vinyl monomer units exemplified above are added as appropriate for the purpose of improving properties such as heat resistance, optical properties, and workability. It is preferable to carry out copolymerization.

In the methacrylic resin of the present embodiment, from the viewpoint of improving weather resistance, heat resistance, fluidity, and thermal stability, the vinyl monomer unit other than the fluorine group-containing vinyl monomer unit is methyl acrylate. Ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, 2-ethylhexyl acrylate and the like are preferably used.
In particular, methyl acrylate, ethyl acrylate, and n-butyl acrylate are preferable, and methyl acrylate is more preferable because it is easily available.

Other vinyl monomer units other than the fluorine group-containing vinyl monomer units can be used alone or in combination of two or more.
The content of the vinyl monomer unit other than the fluorine group-containing vinyl monomer unit, which is copolymerizable with the methacrylic acid ester monomer unit described above, constituting the methacrylic resin of the present embodiment is methacrylic acid. It is preferably 0 to 20 parts by mass with respect to 100 parts by mass in total of the ester monomer unit and at least one fluorine group-containing vinyl monomer unit copolymerizable with the methacrylic acid ester monomer unit. .
From the viewpoint of heat resistance of the methacrylic resin of the present embodiment, it is preferably 20 parts by mass or less, more preferably 1.5 to 15 parts by mass, further preferably 2 to 12 parts by mass, and even more. Preferably it is 3-10 mass parts.

(Molecular weight and molecular weight distribution of methacrylic resin)
The molecular weight and molecular weight distribution of the methacrylic resin of this embodiment will be described.
As for the molecular weight of the methacrylic resin, the weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) is preferably 50,000 to 250,000.
In the molded product of the methacrylic resin of the present embodiment, the weight average molecular weight (Mw) of the methacrylic resin is preferably 50000 or more in order to obtain excellent chemical crack resistance. Moreover, in order for a methacrylic resin to show favorable fluidity | liquidity, it is preferable that a weight average molecular weight (Mw) is 250,000 or less.
Considering the balance between fluidity and chemical crack resistance, the weight average molecular weight (Mw) is preferably from 50,000 to 200,000, more preferably from 75,000 to 190000, and even more preferably from 100,000 to 180,000.
In addition, the molecular weight distribution (weight average molecular weight / number average molecular weight: Mw / Mn) of the methacrylic resin of the present embodiment is preferably 1.0 ≦ Mw / Mn ≦ 2.5 from the viewpoint of thermal decomposition resistance. Furthermore, 1.0 ≦ Mw / Mn ≦ 2.0 is preferable.
The weight average molecular weight (Mw) and the number average molecular weight (Mn) can be measured by gel permeation chromatography (GPC).
Specifically, a standard methacrylic resin is used as the reagent whose monodispersed weight average molecular weight is known in advance, and an analytical gel column in which the high molecular weight component is eluted first is used to prepare a calibration curve from the elution time and the weight average molecular weight. deep. Based on the obtained calibration curve, the molecular weight of each sample can be determined.
The number average molecular weight is a simple average molecular weight per molecule, and is defined by the total weight of the system / number of molecules in the system.

[Method for producing methacrylic resin]
The methacrylic resin of this embodiment can be prepared by any one of bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization.
Bulk polymerization, solution polymerization, and suspension polymerization are preferable, and suspension polymerization is more preferable.
The polymerization temperature may be produced by appropriately selecting an optimum polymerization temperature according to the polymerization method, but is preferably 50 ° C. or higher and 100 ° C. or lower, more preferably 60 ° C. or higher and 90 ° C. or lower.

<Polymerization initiator>
When manufacturing the methacrylic resin of this embodiment, a polymerization initiator may be used.
As the polymerization initiator, when performing radical polymerization, for example, di-t-butyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide, t-butyl peroxyneodecanate, t-butyl peroxypi Valate, dilauroyl peroxide, dicumyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1 -Organic peroxides such as bis (t-butylperoxy) cyclohexane, azobisisobutyronitrile, azobisisovaleronitrile, 1,1-azobis (1-cyclohexanecarbonitrile), 2,2'-azobis -4-methoxy-2,4-azobisisobutyronitrile, 2,2'-a Can be exemplified bis-2,4-dimethylvaleronitrile, 2,2'-azobis-2-methyl butyronitrile general radical polymerization initiator azo such as nitrile.
These may be used alone or in combination of two or more.
A combination of these radical initiators and an appropriate reducing agent may be used as a redox initiator.
These polymerization initiators are generally used in the range of 0 to 1 part by mass with respect to 100 parts by mass of the total amount of all monomers used, taking into consideration the polymerization temperature and the half-life of the initiator. Can be selected as appropriate.
In the case of selecting a bulk polymerization method, a cast polymerization method or a suspension polymerization method, from the viewpoint of preventing resin coloring, the peroxide initiators lauroyl peroxide, decanoyl peroxide, and t- Butyl peroxy-2-ethylhexanoate and the like can be particularly preferably used, and lauroyl peroxide is particularly preferably used.
In addition, when the solution polymerization method is performed at a high temperature of 90 ° C. or higher, a peroxide, an azobis initiator, or the like that has a 10-hour half-life temperature of 80 ° C. or higher and is soluble in the organic solvent to be used is preferable.
Specifically, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, cyclohexane peroxide, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, , 1-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) isobutyronitrile and the like.

<Molecular weight control>
When the methacrylic resin of this embodiment is produced, the molecular weight of the methacrylic resin can be controlled within a range that does not impair the object of the present invention.
For example, the molecular weight can be controlled by using chain transfer agents such as alkyl mercaptans, dimethylacetamide, dimethylformamide, and triethylamine, and iniferters such as dithiocarbamates, triphenylmethylazobenzene, and tetraphenylethane derivatives.
The molecular weight can be adjusted by adjusting the amount of these additives.
When these are used, alkyl mercaptans are preferably used from the viewpoint of handleability and stability. For example, n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-tetradecyl mercaptan, Examples thereof include n-octadecyl mercaptan, 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate) and the like.
These can be appropriately added depending on the molecular weight of the methacrylic resin to be obtained, but generally 0.001 to 3 parts by mass with respect to 100 parts by mass of the total amount of all monomers used. It is used in the range.
Examples of other molecular weight control methods include a method of changing the polymerization method, a method of adjusting the amount of the polymerization initiator, and a method of changing the polymerization temperature.
These molecular weight control methods may be used alone, or two or more methods may be used in combination.

[Other ingredients that can be mixed with methacrylic resin]
(Other resins that can be combined with methacrylic resins)
The methacrylic resin of this embodiment can be used in combination with conventionally known resins as long as the effects of the present invention are not impaired.
The resin to be used is not limited at all, and a known curable resin or thermoplastic resin is preferably used.
Examples of the thermoplastic resin include polypropylene resin, polyethylene resin, polystyrene resin, syndiotactic polystyrene resin, ABS resin (acrylonitrile-butadiene-styrene copolymer), methacrylic resin, AS resin (acrylonitrile). -Styrene copolymer), BAAS resin (butadiene-acrylonitrile-acrylonitrile rubber-styrene copolymer, MBS resin (methyl methacrylate-butadiene-styrene copolymer), AAS resin (acrylonitrile-acrylonitrile rubber-) Styrene copolymer), biodegradable resin, polycarbonate-ABS resin alloy, polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate, polytrimethylene terephthalate Polyalkylene arylate-series resin such as polyethylene naphthalate, polyamide-based resins, polyphenylene ether resins, polyphenylene sulfide resins, phenol resins and the like.
In particular, AS resin and BAAS resin are preferable for improving fluidity, ABS resin and MBS resin are preferable for improving impact resistance, and polyester resin is preferable for improving chemical resistance.
In addition, polyphenylene ether resins, polyphenylene sulfide resins, phenol resins, and the like can be expected to have an effect of improving flame retardancy.
Further, as curable resins, unsaturated polyester resins, vinyl ester resins, diallyl phthalate resins, epoxy resins, cyanate resins, xylene resins, triazine resins, urea resins, melamine resins, benzoguanamine resins, urethane resins, oxetane resins, ketone resins. Alkyd resin, furan resin, styrylpyridine resin, silicone resin, synthetic rubber and the like.
These resins may be used alone or in combination of two or more.

(Additives that can be mixed with methacrylic resins)
In order to impart other characteristics such as rigidity and dimensional stability to the methacrylic resin of the present embodiment, various additives such as phthalate ester, fatty acid ester, Trimellitic acid ester type, phosphoric acid ester type, polyester type plasticizer, higher fatty acid, higher fatty acid ester, higher fatty acid mono-, di- or triglyceride type release agent, polyether type, polyether ester type, Antistatic agents such as polyether ester amides, alkyl sulfonates, alkyl benzene sulfonates, antioxidants, and stabilizers such as UV absorbers, heat stabilizers, light stabilizers, flame retardants, flame retardant aids, Curing agent, curing accelerator, conductivity imparting agent, stress relaxation agent, crystallization accelerator, hydrolysis inhibitor, lubricant, impact imparting agent, slidability improving agent, compatibilizing agent, nucleating agent Strengthening agent, reinforcing agent, flow modifier, colorant, dye, sensitizer, coloring pigment, rubber polymer, thickener, anti-settling agent, anti-sagging agent, inorganic filler, antifoaming agent, coupling Agents, rust inhibitors, antibacterial / antifungal agents, antifouling agents, conductive polymers and the like can also be added.

  For example, examples of the flame retardant include a cyclic nitrogen compound, a phosphorus flame retardant, silicone, caged silsesquioxane or a partial cleavage structure thereof, and silica.

Examples of the thermal stabilizer include antioxidants such as hindered phenol antioxidants and phosphorus processing stabilizers, and hindered phenol antioxidants are preferred.
Specifically, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N′-hexane-1,6-diylbis [3- (3,5-di-tert-butyl) -4-hydroxyphenylpropionamide, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″-(mesitylene-2,4,6- Triyl) tri-p-cresol, 4,6-bis (octylthiomethyl) -o-cresol, 4,6-bis (dodecylthiomethyl) -o-cresol, ethylenebis (oxy) Ethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate, hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3 , 5-Tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5- Tris [(4-tert-butyl-3-hydroxy-2,6-xylin) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di -Tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamine) phenol and the like, and pentaerythritol terakis [3- (3,5-di-ter - butyl-4-hydroxyphenyl) propionate are preferred.

Examples of the ultraviolet absorber include benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, oxazole compounds, malonic acid ester compounds, cyanoacrylate compounds, lactones. Compounds, salicylic acid ester compounds, benzoxazinone compounds, and the like, preferably benzotriazole compounds and benzotriazine compounds.
These may be used independently, may be used individually by 1 type, or may be used in combination of 2 or more types.
Moreover, when adding an ultraviolet absorber, from the viewpoint of molding processability, the vapor pressure (P) at 20 ° C. is preferably 1.0 × 10 ⁻⁴ Pa or less, more preferably 1.0 × 10 ^{−. 6} Pa or less, more preferably 1.0 × 10 ⁻⁸ Pa or less.
“Excellent molding processability” means, for example, that there is little adhesion of the UV absorber to the mold surface during injection molding, and less adhesion of the UV absorber to the roll during film molding.
If it adheres to the roll, for example, it may adhere to the surface of the molded body and deteriorate the appearance and optical properties, so it is not preferable when the molded body is used as an optical material.
Moreover, it is preferable that melting | fusing point (Tm) of an ultraviolet absorber is 80 degreeC or more, More preferably, it is 100 degreeC or more, More preferably, it is 130 degreeC or more, More preferably, it is 160 degreeC or more.
The UV absorber preferably has a weight loss rate of 50% or less, more preferably 30% or less, and even more preferably 15% or less when the temperature is increased from 23 ° C. to 260 ° C. at a rate of 20 ° C./min. Even more preferably, it is 10% or less, and still more preferably 5% or less.

The rubbery polymer is not particularly limited, and for example, rubber particles having a multilayer structure such as general butadiene-based ABS rubber, acrylic-based, polyolefin-based, silicone-based, and fluorine rubber can be used.
In particular, particles having a multilayer structure of a three-layer structure or more are preferable, and rubber polymer particles having a multilayer structure of a three-layer structure or more, such as acrylic rubber particles, are more preferable from the viewpoint of compatibility with a methacrylic resin. .
By using rubber polymer particles having a multilayer structure of three or more layers, heat deterioration during molding processing and deformation of the rubber polymer particles due to heating are suppressed, and heat resistance of the molded body can be maintained. Thermal deformation tends to be suppressed.
The rubbery polymer particles having a multilayer structure of a three-layer structure or more refer to rubber particles having a multilayer structure in which a soft layer made of a rubber-like polymer and a hard layer made of a glassy polymer are laminated, preferably on the inner side To particles having a three-layer structure formed in the order of hard layer-soft layer-hard layer.
By having a hard layer in the innermost layer and the outermost layer, deformation of particles tends to be suppressed, and by having a soft component in the central layer, good toughness tends to be imparted.
Hereinafter, a preferable configuration of the rubbery polymer having a multilayer structure of three layers or more will be described.
In the following, the rubbery polymer is sometimes referred to as acrylic (organic) rubber (particles).

For example, the innermost layer (bi) of the acrylic organic rubber particles is preferably a hard layer, and the above-mentioned methacrylic acid ester monomer, acrylic acid ester monomer, and other aromatic vinyl compound monomers. Or a copolymerizable polyfunctional monomer. Although it does not specifically limit as a methacrylic acid ester monomer in a copolymer, Preferably, methyl methacrylate is mentioned. Moreover, it is although it does not specifically limit as an acrylate monomer in a copolymer, Preferably, n-butyl acrylate and 2-hexyl acrylate are mentioned.
As the aromatic vinyl compound monomer, the same monomers as those used for the methacrylic resin can be used, but styrene or its derivatives are preferably used.
The copolymerizable polyfunctional monomer is not particularly limited, but preferably ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1, One or more of 4-butanediol di (meth) acrylate, allyl (meth) acrylate, triallyl isocyanurate, diallyl maleate, divinylbenzene and the like are used in combination.
Of these compounds, allyl (meth) acrylate is particularly preferred.

The central layer (b-ii) of the rubber polymer particles is preferably a soft layer, and the above-mentioned acrylic acid ester monomer, other aromatic vinyl compound monomer or copolymerizable polyfunctional monomer. It is preferable to consist of the copolymer comprised from a body.
From the viewpoint of imparting excellent toughness to the methacrylic resin, the copolymer that forms the central layer is preferably a copolymer that exhibits soft rubber elasticity, for example, a copolymer that mainly contains an acrylate ester. .
The acrylic ester constituting the central layer (b-ii) is not particularly limited, but preferably includes methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like. These can be used alone or in combination of two or more.
In particular, n-butyl acrylate and 2-hexyl acrylate are more preferable.
Further, styrene or a derivative thereof is preferably used as an aromatic vinyl compound monomer copolymerized with an acrylate ester.
Moreover, as a copolymerizable polyfunctional monomer, the same thing as the copolymerizable polyfunctional monomer used by the innermost layer (bi) can be used, As the content, 0.1% It is preferable for the content to be 5% by mass or more and 5% by mass or less because it has a good cross-linking effect, and the cross-linking is moderate and the rubber elasticity effect tends to increase.

The outermost layer (b-iii) of the rubbery polymer particles is preferably a hard layer and may be composed of a copolymer composed of the above-mentioned methacrylic acid ester monomer and other vinyl monomers. preferable.
Although it does not specifically limit as a methacrylic acid ester monomer in a copolymer, Preferably, methyl methacrylate is mentioned.
Although it does not specifically limit as another vinyl monomer copolymerizable with methacrylic acid ertel, For example, n-butyl acrylate and 2-hexyl acrylate are preferable.

The method for producing rubber polymer particles is not particularly limited, and can be obtained by known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization, and particularly preferably obtained by emulsion polymerization. .
In this case, in the presence of an emulsifier and an initiator, the monomer mixture of the innermost layer (bi) is first added to complete the polymerization, and then the monomer mixture of the central layer (b-ii) is added. By completing the polymerization and then adding the monomer mixture of the outermost layer (b-iii) to complete the polymerization, the multilayer structure particles can be easily obtained as a latex.
The rubber polymer particles can be recovered from the latex as a powder by a known method such as salting out, spray drying or freeze drying.

The inorganic filler is not particularly limited. For example, glass fiber, carbon fiber, calcium silicate fiber, potassium titanate fiber, aluminum borate fiber, glass flake, talc, kaolin, mica, hydrotal Sight, calcium carbonate, zinc carbonate, zinc oxide, calcium monohydrogen phosphate, wollastonite, silica, zeolite, alumina, boehmite, aluminum hydroxide, titanium oxide, silicon oxide, magnesium oxide, calcium silicate, sodium aluminosilicate, Magnesium silicate, ketjen black, acetylene black, furnace black, carbon nanotube, graphite, brass, copper, silver, aluminum, nickel, iron, calcium fluoride, mica, montmorillonite, swellable fluoromica, and apa Ito, and the like.
One kind of inorganic filler may be used, or two or more kinds may be used in combination.
Glass fiber, carbon fiber, glass flake, talc, kaolin, mica, calcium carbonate, calcium monohydrogen phosphate, wollastonite, silica, carbon nanotube, graphite, calcium fluoride, montmorillonite, swelling from the viewpoint of rigidity and strength Fluorine mica and apatite are preferred.
Further, these inorganic fillers may be appropriately subjected to surface treatment for the purpose of being more familiar with the methacrylic resin.

Examples of the colorant include perylene dyes, perinone dyes, pyrazolone dyes, methine dyes, coumarin dyes, quinophthalone dyes, quinoline dyes, anthraquinone dyes, anthraquinone dyes, asdrapyridone dyes, and thioindigo. Dyes, coumarin dyes, isoindolinone pigments, syketopyrrolopyrrole pigments, condensed azo pigments, benzimidazolone pigments, dioxazine pigments, copper phthalocyanine pigments, quinacridone pigments, nickel complex compounds, carbon Black, titanium dioxide, alumina oxide, aluminum hydroxide, silicic acid, zinc oxide, zinc stearate, magnesium stearate, calcium stearate, aluminum stearate, barium sulfate, polymethylsilsesquioxane, copper halide phthalose Nin, ethylene bis-stearic acid amide, ultramarine, ultramarine violet, iron oxide, silicon dioxide, mica, talc, liquid paraffin, magnesium silicate, and the like.
One colorant may be used alone, or two or more colorants may be used in combination.

  As addition amount of the additive mentioned above, 0-10 mass parts is preferable with respect to 100 mass parts of methacrylic resin of this embodiment, 0-8 mass parts is more preferable, and 0-5 mass parts is more preferable.

As a kneading method in the case of mixing the methacrylic resin with the above-described other resins and various additives, a conventionally known method may be used, and it is not particularly limited.
For example, it can be kneaded and produced using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, a Banbury mixer and the like. Among these, kneading with an extruder is preferable in terms of productivity.
The kneading temperature may be in accordance with the preferred processing temperature of the polymer produced according to the present invention, other resins to be mixed, and additives, and is generally in the range of 140 to 300 ° C, preferably in the range of 180 to 280 ° C. .

[Methacrylic resin molded product]
The molded body of the methacrylic resin of this embodiment is obtained by melt-molding the methacrylic resin of this embodiment described above.
Methacrylic resins can be molded by known methods such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding, and the like. Secondary processing molding methods such as molding and vacuum molding can also be used.
Another example is a method in which a methacrylic resin is kneaded and manufactured using a kneader such as a heating roll, kneader, Banbury mixer, extruder, etc., then cooled, pulverized, and further molded by transfer molding, injection molding, compression molding, or the like. Can be mentioned.
The order of mixing the components is not particularly limited as long as the effect of the present invention can be achieved.
Moreover, although the hardening method after mixing thermosetting resin and melt-molding changes with hardeners to be used, there is no limitation in particular.
For example, heat curing, light curing, UV curing, curing by pressure, curing by moisture, and the like can be given.

(Use)
The molded body of the methacrylic resin of the present embodiment can be suitably used as various sanitary molded bodies.
For example, it can be used in various housing applications, kitchens, toilets (toilet bowls, etc.), baths (tubs, bathtubs, etc.), bathrooms and toilets, etc.
In particular, it can be suitably used in applications that require chemical crack resistance and further in applications that place importance on the surface appearance.
The molded body / product using the methacrylic resin can be appropriately subjected to surface functionalization treatment such as hard coat treatment, antireflection treatment, transparent conductive treatment, electromagnetic wave shielding treatment, gas barrier treatment, and the like.

(Characteristic)
In order to use the molded body of the methacrylic resin of this embodiment as a sanitary product, a high level of characteristics as shown below is required in practice.
For example, in the chemical crack solvent resistance evaluation in the examples described later, the critical strain (%) of the molded product of the methacrylic resin is preferably 0.6% or more, more preferably 0.7% or more, 0.8% or more is more preferable. Because the critical strain (%) of the molded product is 0.6% or more, it can be used for various detergents, hair tonic liquids, and other components used in care products that are used for products around water. And excellent chemical crack resistance.

  In the examples described later, the MFR value at 230 ° C. under a load of 3.8 kg is preferably 1.0 g / 10 min or more, more preferably 1.5 g / 10 min or more, and 1.7 g / 10 min or more. Is more preferable, and 2.0 g / 10 min or more is even more preferable. Since the MFR value is 1.0 g / 10 min or more, it is possible to produce medium-sized to large-sized injection-molded bodies required for sanitary products.

  Furthermore, the surface pencil hardness in Examples described later is preferably H or higher, more preferably 2H or higher. Since it is H or more, it can be suitably used for sanitary applications requiring scratch resistance.

Furthermore, it is preferable that the haze value in the Example mentioned later is 5.0% or less. It is more preferably 3.0% or less, and further preferably 2.0% or less.
Since the haze value is 5.0% or less, sanitary products can be suitably used even in cases where glass product substitution, design, and clearness are required. For example, by adding a colorant or the like, a coloring design such as transparent blue or transparent black (smoke color) is possible, and the design is very rich.

  Furthermore, the VICAT softening point (° C.) in Examples described later is preferably 100 ° C. or higher, more preferably 103 ° C. or higher. Since it is 100 ° C. or higher, it has heat resistance against hot water of 70 to 80 ° C. or higher, and thermal deformation is suppressed, so it can be suitably used particularly for sanitary applications such as a bathtub and a wash basin. is there.

  Hereinafter, the present invention will be described with reference to specific examples and comparative examples, but the present invention is not limited thereto.

[Methacrylic resin]
(material)
Methyl methacrylate (MMA) manufactured by Asahi Kasei Chemicals (2.5 ppm of 2,4-di-6-tert-butylphenol) is added as a polymerization inhibitor. What)
2,2,2-trifluoroethyl methacrylate (TFMA): manufactured by Tosoh F-Tech (added with 20 ppm of MEHQ (hydroquinone monomethyl ether) as a polymerization inhibitor)
Methyl acrylate (MA): manufactured by Mitsubishi Chemical (added with 14 ppm of 4-methoxyphenol manufactured by Kawaguchi Chemical Industry as a polymerization inhibitor)
n-octylmercaptan: Arkema Lauroyl peroxide: Nippon Oil & Fats Tricalcium Phosphate: Nippon Kagaku Kogyo Co., Ltd., used as a suspending agent Calcium carbonate Made as a suspension, sodium lauryl sulfate: Wako Pure Chemical, used as a suspension aid

(Measurement method)
<I. Analysis of resin>
(1) Measuring / measuring device for weight average molecular weight of methacrylic resin: Gel Permeation Chromatography (LC-908) manufactured by Nippon Analysis
Column: 1 JAIGEL-4H and 2 JAIGEL-2H in series connection In this column, the high molecular weight elutes early, and the low molecular weight elutes slowly.
Detector: RI (differential refraction) detector Detection sensitivity: 2.4 μV / sec
Sample: 0.450 g of methacrylic resin in chloroform (15 mL) Injection amount: 3 mL
Developing solvent: chloroform, flow rate 3.3 mL / min

The following 10 methacrylic resins (manufactured by EasiCal PM-1 Polymer Laboratories) having different molecular weights and known monodispersed weight average molecular weights were used as standard samples for calibration curves.
Weight average molecular weight Standard sample 1 1,900,000
Standard sample 2 790,000
Standard sample 3 281,700
Standard sample 4 144,000
Standard sample 5 59,800
Standard sample 6 28,900
Standard sample 7 13,300
Standard sample 8 5,720
Standard sample 9 1,936
Standard sample 10 1,020
Under the above conditions, the RI detection intensity with respect to the elution time of the methacrylic resin was measured.
Based on the area area and the calibration curve in the GPC elution curve, the weight average molecular weight (Mw) of the methacrylic resin was determined.

<II. Physical property measurement>
(1) Chemical crack resistance measurement method by bending foam method Chemical crack resistance was evaluated by the measurement method by bending foam method.
FIG. 1 shows a schematic perspective view of an embodiment of chemical crack resistance measurement by the bending foam method.
Injection molding machine: Sumitomo molding machine (SH-25)
Injection molded product: wall thickness 2mm, width 30mm, length 125mm
Injection conditions Molding temperature: 230-250 ° C
Mold temperature: 70 ℃
Cooling time: 20 sec
The molded product of the methacrylic resin of Examples and Comparative Examples, which will be described later, molded under the above conditions was stored in a desiccator for 1 day so as not to absorb water.
Thereafter, as shown in FIG. 1, the molded body (test piece) 10 is placed on the side surface portion (on the curved surface) of the jig 20 having a predetermined size and a quarter-elliptical section using the sample fixing jig 1. Fixed and installed. The size of the test piece 10 is 125 mm (length) × 30 mm (width) × 2 mm (thickness), and in FIG. 1, the location described as “end face of the test piece” is the end in the length direction of the test piece 10. It corresponds to the part.
A gauze 2 containing or applied with the cleaning agent or care cream described in Table 1 below is installed in the center of the injection-molded product (test piece) and in the long side direction of the test piece. The surroundings were wrapped in Saran Wrap (registered trademark) so as not to volatilize, and allowed to stand at 24 hr, 23 ° C., 50% RH.
After 24 hours, the formed body was removed from the fixing jig 1, the generation point Y (mm) of the crack C was read, and the critical strain: ε (%), which is the strain at which the crack C begins to enter, was calculated according to the following formula (3). .
The above measurement was performed on three molded test pieces, and an average value (%) was obtained.
This was used as an index for evaluating chemical cracking solvent resistance.
In the following formula (3), for a, b, and t, a = 127 mm and b = 38.1 mm, and t is 2 mm, which is the thickness of the test piece.

(2) Fluidity measurement method (MFR)
Measurements were performed according to the ISO8257-1 standard.
That is, the melt flow rate (MFR value) under a load of 3.8 kg at 230 ° C. was measured and used as an index of molding fluidity.

(3) Measuring method of surface pencil hardness It measured based on JIS-K5600 standard and made it the parameter | index of surface pencil hardness.

(4) Measuring method of haze value (%) The haze value of a molded piece having a thickness of 3 mm was measured according to the ISO 13468-1 standard.

(5) Evaluation method of heat resistance (VICAT softening point / ° C)
The VICAT softening point was measured according to ISO 306B50 standard.

[Example 1: Methacrylic resin]
A container having a stirrer was charged with 2.5 kg of water, 80 g of tribasic calcium phosphate, 50 g of calcium carbonate, and 0.49 g of sodium lauryl sulfate to obtain a mixed liquid (a ′).
Next, 24 kg of water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (a ′), 18 kg of methyl methacrylate, 2 kg of 2,2,2-trifluoroethyl methacrylate, and 35 g of lauroyl peroxide. , 35 g of n-octyl mercaptan was added.
Thereafter, suspension polymerization was carried out while maintaining about 80 ° C., and after observing an exothermic peak, the temperature was raised to 92 ° C. at a rate of 1 ° C./min. Thereafter, the mixture was aged for 60 minutes to substantially complete the polymerization reaction.
Subsequently, 20 mass% sulfuric acid was added in order to cool to 50 ° C. and dissolve the suspending agent.
Next, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates, and the resulting bead-shaped polymer was washed and dehydrated and dried to obtain polymer fine particles.
This polymer contained 90% by mass of methyl methacrylate units and 10% by mass of 2,2,2-trifluoroethyl methacrylate units.
The weight average molecular weight (Mw) of the polymer was 140,000.

[Example 2: Methacrylic resin]
The same formulation and the same procedure as in Example 1 except that 16 kg of methyl methacrylate, 4 kg of 2,2,2-trifluoroethyl methacrylate, 38 g of lauroyl peroxide and 44 g of n-octyl mercaptan were added.
This polymer contained 80% by mass of methyl methacrylate units and 20% by mass of 2,2,2-trifluoroethyl methacrylate units.
The weight average molecular weight (Mw) of the polymer was 120,000.

[Example 3: Methacrylic resin]
The same formulation and the same procedure as in Example 1 except that 14 kg of methyl methacrylate, 6 kg of 2,2,2-trifluoroethyl methacrylate, 38 g of lauroyl peroxide and 43 g of n-octyl mercaptan were added.
This polymer contained 70% by mass of methyl methacrylate units and 30% by mass of 2,2,2-trifluoroethyl methacrylate units.
The weight average molecular weight (Mw) of the polymer was 120,000.

[Example 4: Methacrylic resin]
The same formulation and the same procedure as in Example 1 except that 13 kg of methyl methacrylate, 7 kg of 2,2,2-trifluoroethyl methacrylate, 38 g of lauroyl peroxide and 38 g of n-octyl mercaptan were added.
This polymer contained 65% by mass of methyl methacrylate units and 35% by mass of 2,2,2-trifluoroethyl methacrylate units.
The weight average molecular weight (Mw) of the polymer was 130,000.

[Example 5: Methacrylic resin]
Except for charging 17 kg of methyl methacrylate, 3 kg of 2,2,2-trifluoroethyl methacrylate, 0.4 kg of methyl acrylate, 38 g of lauroyl peroxide, and 40 g of n-octyl mercaptan, the same amount as in Example 1 was used. Produced in a similar manner.
This polymer has 85% by weight of methyl methacrylate units and 15% by weight of 2,2,2-trifluoroethyl methacrylate units. When the total amount of these units is 100 parts by weight, 2 units of methyl acrylate units are obtained. It contained a part by mass.
The weight average molecular weight (Mw) of the polymer was 130,000.

[Comparative Example 1: Methacrylic resin]
The same formulation and the same procedure as in Example 1 except that 20 kg of methyl methacrylate, 0.4 kg of methyl acrylate, 38 g of lauroyl peroxide and 50 g of n-octyl mercaptan were added.
This polymer contained 2 parts by mass of a methyl acrylate unit when the methyl methacrylate unit was 100 parts by mass.
The weight average molecular weight (Mw) of the polymer was 110,000.

[Comparative Example 2: Methacrylic resin]
The same formulation and the same procedure as in Example 1 except that 4 kg of methyl methacrylate, 16 kg of 2,2,2-trifluoroethyl methacrylate, 38 g of lauroyl peroxide and 40 g of n-octyl mercaptan were added.
This polymer contained 20% by mass of methyl methacrylate units and 80% by mass of 2,2,2-trifluoroethyl methacrylate units.
The weight average molecular weight (Mw) of the polymer was 130,000.

[Comparative Example 3: Methacrylic resin]
The same formulation and the same procedure as in Example 1 except that 11 kg of methyl methacrylate, 9 kg of 2,2,2-trifluoroethyl methacrylate, 38 g of lauroyl peroxide and 45 g of n-octyl mercaptan were added.
This polymer contained 55% by mass of methyl methacrylate units and 45% by mass of 2,2,2-trifluoroethyl methacrylate units.
The weight average molecular weight (Mw) of the polymer was 120,000.

[Comparative Example 4: Methacrylic resin]
The same formulation and the same procedure as in Example 1 except that 19 kg of methyl methacrylate, 1 kg of 2,2,2-trifluoroethyl methacrylate, 38 g of lauroyl peroxide and 50 g of n-octyl mercaptan were added.
This polymer contained 95% by mass of methyl methacrylate units and 5% by mass of 2,2,2-trifluoroethyl methacrylate units.
The weight average molecular weight (Mw) of the polymer was 115,000.

[Comparative Example 5: Mixture of methacrylic resin and tetrafluoroethylene powder]
10 parts by mass of tetrafluoroethylene powder (KTL-20N) manufactured by Kitamura Co., Ltd. was dry blended with respect to 100 parts by mass of the methacrylic resin beads of Comparative Example 1.

[Evaluation of methacrylic resins of Examples 1 to 5]
The methacrylic resin beads of Examples 1 to 5 were melt-extruded using a φ30 mm twin screw extruder set at 230 ° C., and the strands were cooled and cut to obtain resin pellets.
Each pellet was molded at 230 to 250 ° C., and each evaluation was performed according to the physical property evaluation method.
Since the copolymerization ratio of MMA and TFMA was optimal, it was found that fluid molding processing and chemical crack resistance were excellent, transparency and surface hardness were excellent, and heat resistance was also high.
Particularly in Examples 2 and 3, by copolymerizing 20 or 30% by mass of 2,2,2-trifluoroethyl methacrylate units with respect to 80 or 70% by mass of methyl methacrylate units, However, it showed high chemical crack resistance and achieved high transparency, high fluidity, good surface pencil hardness and heat resistance.

[Evaluation of methacrylic resins of Comparative Examples 1 to 4]
The methacrylic resin beads of Comparative Examples 1 to 4 were melt-extruded using a φ30 mm twin screw extruder set at 230 ° C., and the strands were cooled and cut to obtain resin pellets.
Each pellet was molded at 230 to 250 ° C., and each evaluation was performed according to the physical property evaluation method.
Since the copolymerization ratio of MMA and TFMA was inappropriate, Comparative Examples 1 and 4 had low chemical crack resistance, and Comparative Examples 2 and 3 did not have good characteristics in surface hardness and heat resistance.

[Comparative Example 5]
As described above, after dry blending 10 parts by mass of Kitamura Co., Ltd. tetrafluoroethylene powder (KTL-20N) with respect to 100 parts by mass of the methacrylic resin beads of Comparative Example 1, this was adjusted to 240 ° C. It melt-extruded with a set φ30 mm twin-screw extruder, and the strand was cooled and cut to obtain resin pellets.
The obtained pellets were molded at 240 ° C. and evaluated in accordance with the above physical property evaluation methods.
As a result of evaluation, the transparency of the molded product was greatly reduced and the surface hardness was reduced.

The materials used for evaluation of chemical crack resistance are shown below.
Johnson Forward (product name made by Johnson)
Saint Paul (KINCHO product name)
Brabus Hair Tonic (trade name, manufactured by Shiseido)
Nivea Hand Cream (trade name, manufactured by Nivea Kao)

  The methacrylic resin of the present invention and these molded articles are used in various sanitary products, such as various housing applications, kitchens, toilets (toilet bowls, etc.), baths (tubs, bathtubs, etc.), washstands, vanities, etc. As an application resin, it has industrial applicability.

DESCRIPTION OF SYMBOLS 1 Fixing jig 2 Gauze 10 which applied each liquid and solid Test piece 20 Jig

Claims (5)

Methacrylic acid ester monomer unit: 60 to 90% by mass,
At least one fluorine-containing vinyl monomer unit copolymerizable with the methacrylic acid ester monomer unit: 10 to 40% by mass;
A methacrylic resin. When the total of at least one fluorine group-containing vinyl monomer unit copolymerizable with the methacrylic acid ester monomer unit and the methacrylic acid ester monomer unit is 100 parts by mass,
Other than the at least one fluorine group-containing vinyl monomer unit copolymerizable with the methacrylic acid ester monomer unit, other vinyl monomer units copolymerizable with the methacrylic acid ester monomer unit may be acrylic. The methacrylic resin according to claim 1, comprising 0 to 20 parts by mass of an acid ester monomer unit.   The methacrylic resin according to claim 1 or 2, wherein the weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) is 50,000 to 250,000.   A melt-molded article using the methacrylic resin according to any one of claims 1 to 3.   The melt-molded product according to claim 4, which is a sanitary molded product.